CN1791514A - Image device - Google Patents

Abstract

An apparatus for image comprises a mover adapted to move forward and backward within the device along a guide shaft constructed by a shaft body including an arc in at least a part of the cross section, following the reading or recording of image information, and bearings through which the guide shaft extends and which are disposed at two positions in a direction of movement differing from the barycentric position in the mover, each bearing having two slopes with the arc of the guide shaft abutting against the cross section, the angles (thetaf (rad)) and (thetar (rad)) which the two slopes of the bearing form with the vertical being such that cos {pi/2-(thetaf + thetar)} > 0.

Description

image device

technical field

The present invention relates to an image device, comprising: an image recording device that reciprocates along a guide shaft with a recording part facing an image forming surface of a recording medium; An image reading device that moves back and forth.

Background technique

In an image device including an image recording device such as a printer and an image reading device such as a scanner, there are components for reciprocating a movable body within a predetermined range in the device. For example, in an inkjet printer as an image recording device, an inkjet head as a recording unit and an ink cartridge are mounted on a carriage as a moving body, and the carriage is reciprocated in a direction perpendicular to the conveying direction of recording media such as paper. move. The carriage reciprocates the inkjet head within a range that faces the entire image forming surface of the recording medium in a direction perpendicular to the conveying direction of the recording medium.

Therefore, the guide shaft is fixed inside the inkjet printer, and the longitudinal direction of the guide shaft is aligned with the direction perpendicular to the transport direction of the recording medium. The guide shaft passes through a bearing provided on the carriage. The moving direction of the carriage is limited to the lengthwise direction of the guide shaft.

Generally, in the carriage, the bearing through which the guide shaft penetrates is arranged at a position deviated from the center of gravity of the carriage to the upstream or downstream side of the recording medium transport direction so that the guide shaft does not interfere with the ink cartridge and the ink cartridge installed in the center of the carriage. inkjet head. Therefore, a rotational moment centered on the guide shaft acts on the carriage. Furthermore, a force that lifts one end of the carriage in the moving direction by inertial force during acceleration and deceleration and a force that rotates the carriage in a horizontal plane including the guide shaft act on the carriage moving along the guide shaft. When the carriage is displaced out of the moving direction along the guide shaft due to these forces, the interval between the inkjet head and the image forming surface of the recording medium changes, not only noise and vibration are generated when the carriage moves, but also due to the The formed state cannot be kept constant, resulting in a decrease in image quality.

Therefore, in an inkjet printer, the carriage is fixed with respect to the rotation direction centering on the guide shaft so that the carriage does not rotate due to a rotational moment, or fluctuate or yaw due to an inertial force during acceleration and deceleration.

As an example of such a structure, two guide rails are arranged parallel to the guide shaft in the inkjet printer, and a rotation stop member and a pressing member that slide along the respective guide rails are provided on the carriage. The pressing member is pressed against one guide rail with a predetermined pressing force, and a unidirectional rotational force around the guide shaft acts on the carriage. In the direction of the rotational force, the anti-rotation member abuts against the other guide rail, thereby fixing the position of the carriage with respect to the rotational direction centered on the guide shaft.

In this way, by abutting the anti-rotation member and the pressing member on the two guide rails, the rotation of the carriage centered on the guide shaft can be reliably prevented, but this is in a direction perpendicular to the moving direction of the carriage, and the guide shaft is not in the bearing. Internal displacement is the premise.

In addition, an inkjet printer has been proposed (for example, refer to Patent Document 1). As a bearing provided on the carriage, it is not necessary to strictly maintain the working accuracy with the guide shaft, and it has an arc portion that abuts on the cross section of the guide shaft. At least two inclined surfaces of the guide shaft abut against the guide shaft only at two points on the cross section.

In the structure described in Patent Document 1, at the two contact points between the bearing and the guide shaft, the angles formed by the tangential direction and the vertical direction on the outer peripheral surface of the guide shaft are set so that when the carriage accelerates and decelerates The frictional force between the guide shaft and the bearing is greater than the force that makes the bearing slide in the circumferential direction of the guide shaft, thereby causing the carriage to travel with a prescribed accuracy relative to the guide shaft.

Therefore, in the structure described in Patent Document 1, there is also a guide rail to restrict the rotation of the carriage around the guide shaft, and guide the carriage to reciprocate in the direction of the intersection, and set the respective angles according to the following factors, that is, the carriage The weight of the carriage relative to the guide shaft, the position of the center of gravity of the carriage relative to the guide shaft, the distance between the bearings provided on approximately both sides of the carriage, the coefficient of friction between the bearings and the guide shaft, and the drive transmission part of the carriage relative to the guide shaft position, the position of the guide rail relative to the guide shaft, and the acceleration and deceleration applied to the carriage. Accordingly, during acceleration and deceleration of the carriage, the bearing portion of the carriage is prevented from floating from the guide shaft, noise and vibration during acceleration and deceleration can be suppressed, and images can be recorded quietly and with high precision.

And, among the above-mentioned respective angles, the angle formed by the tangential direction and the vertical direction on the outer peripheral surface of the guide shaft is smaller at the contact point on the downstream side of the conveying direction of the recording medium than at the upstream side of the conveying direction, thereby guiding The sliding load of the shaft and the bearing is reduced, the amount of wear at the contact point of the bearing can be suppressed to a minimum, and the durability of the recording device can be improved.

However, according to the configuration described in Patent Document 1, there is a problem that the rotation, undulation, and yaw that occur during acceleration and deceleration of the carriage moving along the guide shaft cannot be reliably restricted. That is, the angles of the two inclined surfaces of the bearing cannot be accurately determined based only on the elements considered in the structure described in Patent Document 1 above. Therefore, vibration and noise are generated when the carriage moves, resulting in deterioration of the image forming state. This problem not only exists in image recording devices such as inkjet printers having reciprocating carriages on which inkjet heads and ink cartridges are installed, but also occurs in scanners and the like having reciprocating units on which lenses and photosensitive elements are installed. in the image reading device.

It is an object of the present invention to provide an image device capable of reliably limiting rotation, heave, and yaw that occur during acceleration and deceleration of the moving body by taking into account all elements acting on the moving body moving along the guide shaft.

Patent Document 1 Japanese Patent Laid-Open Publication No. 2002-137481

Contents of the invention

As means for solving the above-mentioned problems, the present invention has the following configurations.

(1) An image device, characterized in that it has a moving body, and along with the reading or recording of image information, along a guide shaft composed of a shaft body including a circular arc portion in at least a part of the cross section, within the device For reciprocating movement, bearings penetrated by the guide shaft are provided at two places in the moving direction different from the position of the center of gravity of the mobile body. The angles θf(rad) and θr(rad) formed by the two slopes of the bearing and the vertical direction satisfy the relationship cos{π/2-(θf+θr)}>0.

As shown in Figure 14, among the two inclined surfaces of the bearing with angles θf and θr formed with the vertical direction, the load F acting on the guide shaft from one inclined surface and the component E parallel to the other inclined surface satisfy the relationship E= F·cos{π/2-(θf+θr)}. Assuming that the direction of pressing the guide shaft is positive, when the parallel component E is a positive value, this direction becomes the direction in which the guide shaft sinks into the inclined surface of the bearing, and the moving body does not appear to float from the guide shaft. . On the other hand, when the parallel component E has a negative value, this direction becomes the direction in which the guide shaft moves away from the inclined surface of the bearing, and the bearing floats from the guide shaft, so that the positional accuracy cannot be ensured.

In this configuration, the cosine of the angle obtained by subtracting the sum of the angles between the two inclined surfaces of the bearings provided at two positions of the mobile body and the vertical direction from π/2 is a positive value. Therefore, when the direction in which the guide shaft is pressed is positive, the load F acting on the guide shaft from one slope must be a positive value, so the load F parallel to the other slope obtained by multiplying it by a positive cosine value is The component E must also have a positive value, and this component becomes the direction in which the guide shaft sinks into the slope of the bearing. Thereby, it is possible to reliably prevent the moving body from floating from the guide shaft.

(2) The present invention is characterized in that the first and second guide rails are arranged in parallel to the guide shaft, and the moving body is provided with a rotation preventing member and a pressing member that presses and slides on the second guide rail, and the rotation preventing member Sliding against the first guide rail in the rotation direction of the mobile body centered on the guide shaft,

Assume that the mass of the moving body is M, the acceleration of the moving body during acceleration is G, the load acting on the first guide rail from the anti-rotation member is W, and the friction coefficient between the first guide rail and the anti-rotation member is μ. The crimping force acting on the second rail is P, the friction coefficient between the second rail and the pressing member is μ', the coefficient between the guide shaft and the bearing is μ”, the crimping force acting on the second rail from the pressing member and The angle formed by the vertical direction is η,

In the vertical direction, the distance from the contact position of the guide shaft and the bearing to the action point of the moving force of the mobile body is z, the distance to the contact position of the first guide rail and the anti-rotation member is c, and the distance to the center of gravity of the mobile body is The distance is j, the distance to the contact position of the second guide rail and the pressing member is a,

In the horizontal direction perpendicular to the moving direction of the moving body, the distance from the contact position of the guide shaft and the bearing to the center of gravity of the moving body is y, the distance from the contact position of the first guide rail and the anti-rotation component is d, and the distance to the first 2 The distance between the contact position of the guide rail and the pressing part is k,

In the moving direction of the moving body, let the distance between the two bearings be b,

Ff＝{φ-ε-h·tanθr}·cosθr/sin(θf+θr)

+2φ{(μ”·z)/b}(cosθr+cosθf)·cosθr/sin2(θf+θr)

Fr'＝{φ+ε-h·tanθf}·cosθf/sin(θf+θr)

-2φ{(μ”·z)/b}(cosθr+cosθf)·cosθf/sin2(θf+θr)

Among them, φ=(M/2)+P·cosη

ε＝{G·M(j-z)+μ·W(c-z)+2μ'·P(a-z)}/b

h＝{G·M·y+2μ”·P·d+μ·W·k}/b

The angles θf(rad) and θr(rad) are determined so that the load Ff(gf) on the inclined surface of the moving center of gravity side of the bearing on the downstream side in the moving direction calculated by the above formula and the load Ff(gf) on the bearing on the upstream side in the moving direction The load Fr'(gf) applied to the slope on the opposite side of the center of gravity of the movement is a positive value.

In this structure, when the moving body accelerates, it is considered that the load acting on the guide shaft from the inclined surface on the side of the moving center of gravity of the bearing on the downstream side of the moving direction and the opposite direction of the load on the moving center of gravity side of the bearing on the upstream side of the moving direction are considered. The side slope acts on all elements of the load on the guide shaft, determining the angle formed by the two slopes of the bearing with the vertical. Therefore, when the mobile body accelerates, the inclined surface of the bearing does not separate from the guide shaft due to the load acting on the guide shaft from the inclined surface of the bearing, and the mobile body does not float.

(3) The present invention is characterized in that the first and second guide rails are arranged in parallel to the guide shaft, and the moving body is provided with a rotation preventing member and a pressing member that presses and slides in contact with the second guide rail, and the rotation preventing member Sliding against the first guide rail in the rotation direction of the mobile body centered on the guide shaft,

Assume that the mass of the moving body is M, the acceleration of the moving body during acceleration is G, the load acting on the first guide rail from the anti-rotation member is W, and the friction coefficient between the first guide rail and the anti-rotation member is μ. The crimping force acting on the second rail is P, the friction coefficient between the second rail and the pressing member is μ', the coefficient between the guide shaft and the bearing is μ”, the crimping force acting on the second rail from the pressing member and The angle formed by the vertical direction is η,

In the vertical direction, the distance from the contact position of the guide shaft and the bearing to the action point of the moving force of the mobile body is z, the distance to the contact position of the first guide rail and the anti-rotation member is c, and the distance to the center of gravity of the mobile body is The distance is j, the distance to the contact position of the second guide rail and the pressing member is a,

In the horizontal direction perpendicular to the moving direction of the moving body, the distance from the contact position of the guide shaft and the bearing to the center of gravity of the moving body is y, the distance from the contact position of the first guide rail and the anti-rotation component is d, and the distance to the first 2 The distance between the contact position of the guide rail and the pressing part is k,

In the moving direction of the moving body, let the distance between the two bearings be b,

Ff'＝{φ+ε+h·tanθr}·cosθr/sin(θf+θr)

-2φ{(μ”·z)/b}(cosθr+cosθf)·cosθr/sin2(θf+θr)

Fr＝{φ-ε+h·tanθr}·cosθr/sin(θf+θr)

+2φ{(μ”·z)/b}(cosθr+cosθf)·cosθf/sin2(θf+θr)

Among them, φ=(M/2)+P·cosη

ε＝{G·M(j-z)+μ·W(c-z)+2μ'·P(a-z)}/b

h＝{G·M·y+2μ”·P·d+μ·W·k}/b

The angles θf(rad) and θr(rad) are determined so that the load Ff'(gf) on the slope on the opposite side of the moving gravity center side of the bearing on the downstream side of the moving direction calculated by the above formula and the upstream side of the moving direction The load Fr(gf) on the opposite side of the moving center of gravity side of the bearing is a positive value.

In this structure, when the moving body is decelerated, it is considered that the load acting on the guide shaft from the inclined surface on the side opposite to the center of gravity side of the bearing on the downstream side of the moving direction and the load acting on the guide shaft from the center of gravity side of the bearing on the upstream side of the moving direction are considered. The inclined plane acts on all elements of the load on the guide shaft, and the angle formed by the two inclined planes of the bearing and the vertical direction is determined. Therefore, when the moving body decelerates, the inclined surface of the bearing does not separate from the guide shaft due to the load acting on the guiding shaft from the inclined surface of the bearing, and the moving body does not float.

(4) The present invention is characterized in that the maximum value of the moment of the moving body acting on the moving body due to external disturbance is set to Mm (gf·mm), and the center of gravity side of the moving body of the bearing on the downstream side of the moving direction is set to The load Ff(gf) borne by the inclined surface of the bearing and the load Fr'(gf) borne by the inclined surface on the opposite side of the moving center of gravity side of the bearing on the upstream side of the moving direction satisfy the following relationship:

Ff·cos{π/2-(θf+θr)}·b/2＞Mm

Fr'·cos{π/2-(θf+θr)}·b/2>Mm.

In this structure, when the moving body accelerates, it is considered that the load acting on the guide shaft from the inclined surface on the side of the moving center of gravity of the bearing on the downstream side of the moving direction and the opposite direction of the load on the moving center of gravity side of the bearing on the upstream side of the moving direction are considered. The side slope acts on all elements of the load on the guide shaft, determining the angle formed by the two slopes of the bearing with the vertical. Therefore, when the mobile body accelerates, the inclined surface of the bearing does not separate from the guide shaft due to the load acting on the guide shaft from the inclined surface of the bearing, and the mobile body does not float.

(5) The present invention is characterized in that the maximum value of the moment of the moving body acting on the moving body due to external disturbance is set to Mm (gf·mm), and the center of gravity side of the moving body of the bearing on the downstream side of the moving direction is The load Ff'(gf) on the slope on the opposite side of the bearing and the load Fr(gf) on the slope on the side of the moving center of gravity of the bearing on the upstream side of the moving direction satisfy the following relationship:

Ff’·cos{π/2-(θf+θr)}·b/2＞Mm

Fr·cos{π/2-(θf+θr)}·b/2>Mm.

In this structure, when the moving body is decelerated, it is considered that the load acting on the guide shaft from the inclined surface on the side opposite to the center of gravity side of the bearing on the downstream side of the moving direction and the load acting on the guide shaft from the center of gravity side of the bearing on the upstream side of the moving direction are considered. The inclined plane acts on all elements of the load on the guide shaft, and the angle formed by the two inclined planes of the bearing and the vertical direction is determined. Therefore, when the moving body decelerates, the inclined surface of the bearing does not separate from the guide shaft due to the load acting on the guiding shaft from the inclined surface of the bearing, and the moving body does not float.

(6) The present invention is characterized in that the load Ff(gf) applied to the inclined surface on the moving center of gravity side of the bearing on the downstream side in the moving direction is opposite to the moving center of gravity side of the bearing on the upstream side in the moving direction. The load Fr'(gf) on the slope is approximately equal.

In this structure, when the mobile body accelerates, the angle formed by the slope of each bearing and the vertical direction is set so that the load acting on the guide shaft from the slope of the bearing on the downstream side of the moving direction on the side of the center of gravity of the moving body, and the load from the The load on the guide shaft is substantially equal to the inclined surface on the opposite side of the moving center of gravity side of the bearing on the upstream side of the moving direction. Therefore, when the mobile body accelerates, substantially equal moments are generated on the slopes of the respective bearings, and the movement of the mobile body is stabilized.

(7) The present invention is characterized in that the load Ff'(gf) applied to the slope on the side opposite to the moving center of gravity side of the bearing on the downstream side of the moving direction and the moving gravity center side of the bearing on the upstream side of the moving direction The load Fr(gf) on the inclined plane is roughly equal.

In this structure, when the moving body decelerates, the angle formed by the slope of each bearing and the vertical direction is set so that the load acting on the guide shaft from the slope on the side opposite to the moving center of gravity side of the bearing on the downstream side of the moving direction, It is approximately equal to the load acting on the guide shaft from the inclined surface on the moving center of gravity side of the bearing on the upstream side in the moving direction. Therefore, when the mobile body accelerates, substantially equal moments are generated on the slopes of the respective bearings, and the movement of the mobile body is stabilized.

(8) The present invention is characterized in that the angles θf (rad) and θr (rad) formed by the two slopes of the bearing and the vertical direction are determined respectively, and they satisfy the relationship abs[Δ(μ·W+2·μ '·P+μ"·T)/Δ{57.3·(θf+θr)}]≤2.

There is a relationship shown in Figure 11 between the sum of the angles formed by the two slopes of the bearing and the vertical direction, and the sliding resistance of the slopes and the guide shaft, and the change rate of the sliding resistance relative to the sum of the angles of the slopes is less than 2. , the value of the sliding resistance is approximately the minimum value.

In this structure, the angle of the slope is determined so that the rate of change of the sliding resistance with respect to the sum of the angles of the slope is less than 2. Therefore, when the mobile body moves, the sliding resistance generated between the bearing and the guide shaft is suppressed to a low value, and the mobile body moves smoothly.

(9) The present invention is characterized in that, in the bearings arranged at two places in the moving direction of the moving body, angles θf(rad) and θr(rad) formed by the two slopes with the vertical direction are different from each other.

In this configuration, two bearings having different inclination angles of the slopes are arranged in the moving direction of the moving body. Therefore, the mobile body can reciprocate in a stable state even when the moving speed is different between the forward time and the backward time.

Description of drawings

FIG. 1 is an external view of an inkjet printer that is an image device according to an embodiment of the present invention.

Fig. 2 is a side view of the main part including the carriage of the above inkjet printer.

Fig. 3 is a rear view of the main part including the carriage of the inkjet printer.

Fig. 4 is a side view specifically showing a bearing provided on the above-mentioned carriage.

Fig. 5 is a front view illustrating a calculation method for determining the angle formed by the inclined surface of the bearing and the vertical direction.

FIG. 6 is a side view illustrating the calculation method.

FIG. 7 is a front view illustrating the calculation method.

FIG. 8 is a front view illustrating the calculation method.

FIG. 9 is a front view illustrating the calculation method.

FIG. 10 is a front view illustrating the calculation method.

Fig. 11 is a side view of a bearing illustrating this calculation method.

FIG. 12 is a plan view illustrating the calculation method.

Fig. 13 is a side view of a bearing illustrating this calculation method.

Fig. 14 is a side view of a bearing illustrating this calculation method.

Fig. 15 is a diagram showing values of various elements in an embodiment of the present invention.

Fig. 16 is a graph showing the relationship between the angle of one slope of the bearing and the moment in the direction parallel to the other slope.

Fig. 17 is a graph showing the relationship between the sum of the angles of the two slopes of the bearing and the sliding resistance.

18 is a configuration diagram showing a carriage used in an inkjet printer according to another embodiment of the present invention.

Fig. 19 is a diagram showing values of various elements in another example of the present invention.

Detailed ways

FIG. 1 is an external view of an inkjet printer that is an image device according to an embodiment of the present invention. The inkjet printer 1 is composed of a paper feed unit 1a, a separation unit 1b, a transport unit 1c, a printing unit 1d, and a discharge unit 1e. The paper feed unit 1 a feeds paper P which is a recording medium when printing, and has a paper feed tray 2 and a pickup roller 3 . The paper feed unit 1 a stores paper P when not printing.

The separation unit 1b supplies the paper P supplied from the paper feeding unit 1a to the transport unit 1c one by one, and is composed of a paper feeding roller and a separation device (not shown). The frictional force of the pad portion (contact portion with the paper P) and the paper P of the separation device is greater than the frictional force between the individual papers P. Also, the frictional force between the paper feed roller and the paper P is greater than the frictional force between the pad of the separation device and the paper P and the frictional force between the individual papers P. Therefore, even if a plurality of sheets P are simultaneously conveyed from the paper feeding section 1a to the separating section 1b, the sheets P are separated by the paper feeding roller and the separating device, and only the uppermost paper P is guided to the conveying section 1c.

The conveying section 1c has a guide plate 4 and conveying rollers 5, and conveys the sheets P fed one by one from the separating section 1b to the printing section 1d. When the conveying roller 5 sends the paper P between the inkjet head 6 and the platen 10 , it adjusts the conveying speed of the paper P and the timing of starting conveyance, so that the ink ejected from the inkjet head 6 adheres to the proper position of the paper P.

The printing unit 1d is for printing an image on the image forming surface of the paper P transported by the transport roller 5 of the transport unit 1c, and has: an inkjet head 6 for ejecting ink corresponding to the image; and an ink cartridge 7 for accommodating ink supplied to the inkjet head. ; the carriage 8 that carries the inkjet head 6 and the ink cartridge 7 to reciprocate; the guide shaft 9 that guides the moving direction of the carriage 8 ; and the platen 10 that holds the paper P during printing.

The discharge unit 1 e discharges the paper P printed on the image forming surface to the outside of the inkjet printer 1 , and includes discharge rollers 11 and 12 and a paper discharge tray 13 . The paper P that has passed through the printing unit 1 d is discharged onto a paper discharge tray 13 via discharge rollers 11 and 12 .

In this configuration, the inkjet printer 1 performs printing through the following operations. First, a print request based on image information is issued to the inkjet printer 1 from a computer (not shown). The inkjet printer 1 that has received the print request sends out the paper P on the paper tray 2 by the pickup roller 3 . Then, the sent paper P is sent to the conveying part 1c one by one through the paper feeding roller and the separating part 1b, and then is conveyed to the inkjet head 6 and the platen 10 of the printing part 1d through the conveying roller 5 of the conveying part 1c. between.

In the printing unit 1 d , ink is ejected from the inkjet head 6 onto the image forming surface of the paper P on the platen 10 in accordance with the image information. At this time, the paper P temporarily stops on the platen 10 . While ejecting the ink, the carriage 8 moves by 1 line along the guide shaft 9 in the main scanning direction perpendicular to the sheet conveying direction. When the carriage 8 reaches one end side of the moving range, the paper P is conveyed by a certain width in the paper conveying direction on the platen 10 , that is, in the sub-scanning direction. In the printing unit 1 d , the image information is printed on the entire surface of the paper P by repeatedly performing stoppage of paper P conveyance, movement of the carriage 8 accompanying the driving of the inkjet head 6 , and paper P conveyance. The paper P on which an image is printed is discharged onto a paper discharge tray 13 by discharge rollers 11 and 12 .

2 and 3 are a side view and a rear view of main parts including a carriage of the inkjet printer described above. The carriage 8 is provided with a rotation preventing member 81 , a pressing member 82 , a belt frame 83 and a bearing 84 . The anti-rotation member 81 abuts against the first guide rail 31 . The pressing member 82 is in pressure contact with the second rail 32 . The guide rails 31 and 32 are arranged in parallel with the guide shaft 9 inside the inkjet printer 1 . A part of the drive belt 33 is fixed to the conveyor frame 83 . The guide shaft 9 passes through the bearing 84 .

The driving belt 33 fixed to the belt frame 83 is stretched between a driving pulley and a driven pulley (not shown). The drive pulley is fixed to the rotating shaft of a drive motor (not shown). Therefore, the carriage 8 is transmitted with the rotation of the drive motor via the drive belt 33 , and reciprocates along the guide shaft 9 .

The bearing 84 through which the guide shaft 9 penetrates is arranged on the rear side lower part of the carriage 8 , and is located below the rear side than the center of gravity C of the carriage 8 . Therefore, the carriage 8 rotates in the arrow A direction around the guide shaft 9 . In order to restrict this rotation, a rotation stop member 81 provided on the upper portion of the carriage 8 abuts against the first guide rail 31 toward the front side. And, when vibration and impact are applied to the inkjet printer 1, the carriage 8 rotates in the arrow B direction. In order to restrict this rotation, a pressing member 82 provided on the upper portion of the carriage 8 presses against the second guide rail 32 toward the obliquely upward direction on the rear side.

In addition, as can be seen from the rear view of FIG. two nearby.

Fig. 4 is a side view specifically showing a bearing provided on the above-mentioned carriage. The bearing 84 has a front inclined surface 84 a and a rear inclined surface 84 b constituting a part of the inner peripheral surface. The bearing 84 abuts against the guide shaft 9 with inclined surfaces 84a, 84b. Therefore, it is not necessary to strictly define the inner diameter of the bearing 84 in consideration of fit with the guide shaft 9 .

And, in order to utilize two slopes 84a, 84b to clamp the circumferential surface of the guide shaft 9, the angles θf and θr formed by the two slopes 84a and 84b with the vertical direction must satisfy the relationship 0<(θf+θr)<π, so it is necessary The relation cos{π/2-(θf+θr)}>0 is satisfied.

In this way, by setting the cosine of the angle obtained by subtracting the sum of the angles formed by the two inclined surfaces 84a, 84b of the bearings 84 provided at two places of the carriage 8 and the vertical direction from π/2 to be a positive value, the When the direction of pressing the guide shaft 9 is positive, the load acting on the guide shaft 9 from one inclined surface 84a is always a positive value, so the component parallel to the other inclined surface 84b obtained by multiplying it by a positive cosine value is also It is always a positive value, and this component becomes the direction in which the guide shaft 9 sinks into the slopes 84 a and 84 b of the bearing 84 , and it is possible to reliably prevent the carriage 8 from floating from the guide shaft 9 .

However, the angles θf and θr need to be determined in consideration of the moment acting on the carriage 8 . That is, a heave moment that urges the front and rear ends of the carriage 8 in the moving direction upward or downward, a rotational moment around the guide shaft 9, and a yaw moment that urges the front and rear ends of the carriage 8 in the moving direction to the front side or the back side. , acting on carriage 8.

Hereinafter, a calculation method for specifying the angle formed by the inclined surface of the bearing and the vertical direction will be described using FIGS. 5 to 14 .

When the carriage 8 moves from the left side to the right side in Fig. 5, suppose the mass of the carriage 8 is M, the acceleration acting on the carriage 8 during acceleration is G, the load acting on the anti-rotation part 81 is W, and the anti-rotation The coefficient of friction between the member 81 and the first guide rail 31 is μ, the pressing force of the pressing member 82 is P, and the coefficient of friction between the pressing member 82 and the second guide rail 32 is μ', acting on the downstream side of the moving direction (right side ) The vertical load component of the bearing 84 is S, the horizontal load component of the bearing 84 acting on the downstream side of the moving direction is h, and the vertical load component of the bearing 84' acting on the upstream side (left side) of the moving direction is S', the effect The horizontal load component of the bearing 84' on the upstream side of the moving direction is h', the friction coefficient between the bearings 84, 84' and the guide shaft 9 is μ", and the pressing force P acting on the second guide rail 32 from the pressing member 82 and The angle that the vertical direction forms is η; The distance is z, the distance to the contact position of the first guide rail 31 and the anti-rotation member 81 is c, the distance to the center of gravity of the carriage 8 is j, and the distance to the contact position of the second guide rail 32 and the pressing member 82 is a ; In the horizontal direction perpendicular to the moving direction of the carriage 8, the distance from the contact position of the guide shaft 9 and the bearings 84, 84' to the center of gravity of the carriage 8 is y, to the first guide rail 31 and the anti-rotation member 81 The distance to the contact position of the second guide rail 32 and the contact position of the pressing member 82 is d, and the distance to the contact position of the second guide rail 32 and the pressing member 82 is k; in the moving direction of the carriage 8, the axial distance between the two bearings 84 and 84' is b.

The heave moment in this case is obtained by the following formula as shown in FIG. 5 .

M+2·P·cosη=S+S'

In addition, the rotational moment is obtained by the following formula as shown in FIG. 6 .

W·c＝M·y+P·cosη·d+P·sinη·a

Therefore, the load W acting on the anti-rotation member 81 is:

∴W＝(M·y+P·cosη·d+P·sinη·a)/c

Here, the inertial force α acting on the carriage 8 is as shown in Figure 7:

2·α·(b/2)＝G·M·e

∴α＝G·M·(j-z)/b

Moreover, the sliding resistance β of the anti-rotation member 81 is shown in FIG. 8 as follows:

2·β·(b/2)=μ·W·(c-z)

∴β=μ·W·(c-z)/b

In addition, as shown in FIG. 9, the sliding resistance γ of the pressing member 82 is:

2·γ·(b/2)=2·μ’·P(a-z)

∴γ=2·μ’·P(a-z)/b

In addition, the sliding resistance δ of the guide shaft 9, as shown in FIGS. ) The loads on the inclined surface 84b are Ff and Fr, and the loads acting on the front side inclined surface 84a' and the back side inclined surface 84b' of the bearing 84' on the upstream side of the moving direction of the carriage 8 are respectively Ff' and Fr', then

2·δ·(b/2)=μ”·(Ff’+Fr’+Ff+Fr)·z

∴δ＝μ”·(Ff’+Fr’+Ff+Fr)·z/b

Therefore, the vertical loads S and S' of the bearings 84 and 84' are

S=(M/2)+P·cosη-α-β-γ+δ

S'=(M/2)+P·cosη+α+β+γ-δ

On the other hand, the yaw moment of the carriage 8 is obtained by the following formula as shown in FIG. 12 ,

2·h·(b/2)＝G·M·y+2·μ”·P·d+μ·W·k

The horizontal load component h acting on the bearings 84, 84' is

h＝G·M·y/b+2·μ”·P·d/b+μ·W·k/b

According to the above results, the vertical load component S and the horizontal component h of the bearing 84 acting on the downstream side of the moving direction, and the vertical load component S' and horizontal component h of the bearing 84' acting on the upstream side of the moving direction, as shown in Figure 13 and shown in Figure 14 respectively for

S'＝Ff'·sinθf+Fr'·sinθr               … Formula 1

h＝Ff’·cosθf-Fr’·cosθr ……Equation 2

S＝Ff·sinθf+Fr·sinθr ……Equation 3

h＝-Ff cosθf+Fr cosθr ... Formula 4

here,

(M/2)+P·cosη=φ

(α+β+γ)=ε

Then according to formula 3, we get

φ-ε+μ "(FF '+FR’+FF+FR) · Z/B = FF · sinθf+FR · sinθr ...

According to formula 1 get

φ+ε-μ”(Ff’+Fr’+Ff+Fr) z/b=Ff’ sinθf+Fr’ sinθr ... Formula 1'

And, according to (Equation 2)-(Equation 4) get

Ff'=(Fr'+Fr) cosθr/cosθf-Ff

According to formula 2 get

Ff'=Fr'·cosθr/cosθf+h/cosθf

According to formula 4 get

Ff＝Fr·cosθr/cosθf+h/cosθf

Substitute these into equation 3' to get

Fr’{(1+cosθr)/cosθf}μ”·z/b

+Fr{(cosθf+cosθr)/cosθf}·μ”·z/b

-Fr sin(θf+θr)/cosθf＝-h tanθf-φ+ε

Further, when the 2nd and 3rd items on the left are extracted, we get

Fr·(1/cosθf)·{(cosθf+cosθr)·μ”·z/b-sin(θf+θr) …Equation 5

Arranging Fr' to get

Fr’＝-Fr·{b/(μ”·z)/(cosθr+cosθf)}·ε

-h·b·sinθf/{μ”·z(cosθf+cosθr)}

-φ·b·cosθf/{μ”·z(cosθf+cosθr)}

+ε·b·cosθf/{μ”·z(cosθf+cosθr)}

Here, the first item on the right is

-Fr·{1-b·sin(θf+θr)/(μ”·z)/(cosθr+cosθf)} ……Equation 6

And, according to formula 1' and formula 5, we get

Fr'{(μ”·z)/b}(cosθr+cosθf)/cosθf+sin(θf+θr)/cos(θr)}+Fr(μ”·z/b)(cosθr+cosθf)/cosθf ＝φ+ε-h · tanθf ... Formula 7

According to formula 7 get

Fr＝(φ-ε+h·tanθf)·cosθf/sin(θf+θr)

+2φ(μ”·z/b)(cosθr+cosθf)·cosθf/sin2(θf+θr)……Equation 8

Substituting formula 8 into formula 4, the condition for finding Ff≥0 is

Ff＝(φ-ε-h·tanθr)·cosθr/sin(θf+θr)

+2·φ(μ”·z/b)(cosθr+cosθf)·cosθr/sin2(θf+θr) ……Equation 9

On the other hand, substituting Equation 8 into Equation 6, the condition for Fr'≥θ is obtained as

Fr'＝(-h·tanθf+φ+ε)·cosθf/sin(θf+θr)

-2φ(μ”·z/b)(cosθr+cosθf)·cosθf/sin2(θf+θr)……Equation 10

Further, substitute formula 10 into formula 2 to get

Ff'＝(φ+ε+h·tanθr)·cosθr/sin(θf+θr)

-2φ(μ”·z/b)(cosθr+cosθf)·cosθr/sin2(θf+θr)……Equation 11

Figure 15 shows the values of various elements in the embodiment of the angles θf and θr formed by the inclined surfaces 84a, 84b of the bearing 84 and the vertical direction through the above calculations.

As described above, considering all the elements that affect the load acting on the guide shaft 9 from the respective two slopes 84a, 84b, 84a', 84b' of the bearings 84, 84', the two slopes 84a, 84a, 84b' of the bearings 84, 84' are determined. The angles 84b, 84a', 84b' form with the vertical. Therefore, when the carriage 8 accelerates and decelerates, the carriage 8 can be reliably prevented from floating, and the slopes 84a, 84b, 84a', 84b' of the bearings 84, 84' will not separate from the guide shaft 9.

In addition, assuming that the maximum value of the moment of the moving carriage 8 due to external disturbance is Mm (gf·mm), the two slopes 84a, 84b, 84a', 84b' from the bearings 84, 84' can be made The loads Ff, Fr, Ff', Fr' acting on the guide shaft 9 satisfy the following relationship:

Ff·cos{π/2-(θf+θr)}·b/2＞Mm

Fr’·cos{π/2-(θf+θr)}·b/2＞Mm

Ff’·cos{π/2-(θf+θr)}·b/2＞Mm

Fr·cos{π/2-(θf+θr)}·b/2>Mm.

Thereby, the angles θf, θr, θf', θr' can be determined such that the angles in the direction parallel to the slope facing the load acting on the guide shaft 9 from the slopes 84a, 84b, 84a', 84b' of the bearings 84, 84' The component is larger than the maximum value of moment acting on the moving carriage 8 due to external disturbance. Therefore, even when external disturbances such as vibration of the inkjet printer 1 act, the floating of the carriage 8 can be prevented more reliably, and the slopes 84a, 84b, 84a', 84b' of the bearings 84, 84' will not fall from the Guide shaft 9 leaves.

And, according to the relationship between the slope angle shown in FIG. 16 and the direction moment parallel to the facing slope, it is possible to make the load Ff (gf) acting on the guide shaft 9 from the front side slope 84a of the bearing 84 on the downstream side in the moving direction and the load Ff (gf) from the moving direction. The load Fr'(gf) acting on the guide shaft 9 from the back side slope 84b' of the bearing 84' on the upstream side in the moving direction, and the load Ff'(gf) acting on the guide shaft 9 from the back side slope 84b of the bearing 84 on the downstream side in the moving direction gf) is substantially equal to the load Fr(gf) acting on the guide shaft 9 from the front side inclined surface 84a' of the bearing 84' on the upstream side in the movement direction.

Accordingly, when the carriage 8 accelerates and decelerates, approximately equal moments are generated on the inclined surfaces 84a, 84b, 84a', 84b' of the bearings 84, 84', and the carriage 8 can be moved stably.

In addition, the angles θf and θr formed by the two slopes of the bearings 84, 84' and the vertical direction can be determined, so that they satisfy the relationship abs[Δ(μ·W+2·μ'·P+μ"·T)/Δ {57.3·(θf+θr)}]≤2 (wherein, 57.3 (=180/π) is a coefficient for converting from rad to deg).

Thus, as shown in FIG. 17 , in the range where the rate of change of the sliding resistance relative to the sum of the angles formed by the two slopes of the bearing 84 and the vertical direction is less than 2, the value of the sliding resistance is approximately the minimum value, so the carriage can be The sliding resistance generated between the bearing 84 and the guide shaft 9 during the movement of the carriage 8 is suppressed to a small value, so that the carriage 8 can move smoothly.

In addition, as shown in FIG. 18(A), in the bearings 84, 84' arranged at two places in the moving direction of the carriage 8, the angles θf and θr formed by the two slopes with the vertical direction can be made different from each other. In the example shown in Fig. 18, the angle θr formed by the back side slope 84b of one bearing 84 (Fig. 8(B)) and the vertical direction is positive, and the back side of the other bearing 84' (Fig. 8(C)) The angle θr' formed by the slope 84b' and the vertical direction has a negative value.

This makes it possible to reciprocate the carriage 8 in a stable state even when the moving speed of the carriage 8 is different between forward and backward.

Fig. 19 shows the values of each element of the carriage in which the left and right bearings 84, 84' shown in Fig. 18 have different inclination angles and the carriage in which the pressing member 82 is omitted. In this embodiment, the load by the pressing member 82 is set to 0, and the angles of the inclined surfaces 84a, 84b, 84a', 84b' of the bearings 84, 84' are calculated by the calculation method described above.

In the example shown in FIG. 19, when the acceleration is 2G, the angle of the front side slope 84a of the bearing 84 on the downstream side of the moving direction is 29°, and the angle of the back side slope 84b' of the bearing 84' on the upstream side of the moving direction is -8°. . And, when the acceleration is 0.8G, the angle of the front side inclined surface 84a of the bearing 84 on the downstream side in the moving direction is 41°, and the angle of the back side inclined surface 84b' of the bearing 84' on the moving direction upstream side is 7°.

Therefore, when the carriage 8 moves in the right direction with an acceleration of 2G and in the left direction with an acceleration of 0.8G, the angle of the front side slope 84a of the right bearing 84 is 29°, and the angle of the back side slope 84b is 7°. °, the angle of the front side slope 84a' of the left side bearing 84' is 41°, and the angle of the back side slope 84b' is -8°.

In addition, in the above description, as the image device of the present invention, an inkjet printer having a carriage as a movable body has been described as an example, but the present invention can be similarly implemented in other image devices such as an image reading device. .

Claims (9)

1. an image device is characterized in that having moving body, is accompanied by reading or record of image information, comprises the axis of guide that the axis body of arc sections constitutes along at least a portion by the cross section, in device, move back and forth,

Two places at the moving direction different with the position of centre of gravity of described moving body are provided with the bearing that is connected by the described axis of guide, the cross section of this bearing comprises two inclined-planes of the arc sections of the butt axis of guide, angle θ f (rad) and satisfied cos{ pi/2-(the θ f+ θ r) that concern of θ r (rad) that two inclined-planes that make this bearing form with vertical direction respectively }＞0.

2. image device according to claim 1 is characterized in that,

With the 1st and the 2nd guide rail and described axis of guide configured in parallel, and spline parts and crimping are set on described moving body the pressing component that the 2nd guide rail slides, these spline parts the 1st guide rail at the direction of rotation butt that with the axis of guide is the moving body at center and are slided,

If the quality of moving body is M, acceleration during the acceleration of moving body is G, the loading that acts on the 1st guide rail from the spline parts is W, coefficient of friction between the 1st guide rail and the spline parts is μ, the crimp force that acts on the 2nd guide rail from pressing component is P, and the coefficient of friction between the 2nd guide rail and the pressing component is μ ', and the coefficient between the axis of guide and the bearing is μ "; acting on the angle that the crimp force of the 2nd guide rail and vertical direction form from pressing component is η

In vertical direction, if the distance from the contact position of the axis of guide and bearing to the application point of the locomotivity of moving body is z, be c to the distance of the contact position of the 1st guide rail and spline parts, be j to the distance of the position of centre of gravity of moving body, distance to the contact position of the 2nd guide rail and pressing component is a

In the horizontal direction vertical with the moving direction of moving body, if the distance from the contact position of the axis of guide and bearing to the position of centre of gravity of moving body is y, distance to the contact position of the 1st guide rail and spline parts is d, is k to the distance of the contact position of the 2nd guide rail and pressing component

At the moving direction of moving body, the distance of shaft centers of establishing two bearings is from being b,

Ff＝{φ-ε-h·tanθr}·cosθr/sin(θf+θr)

+2φ{(μ”·z)/b}(cosθr+cosθf)·cosθr/sin2(θf+θr)

Fr’＝{φ+ε-h·tanθf}·cosθf/sin(θf+θr)

-2φ{(μ”·z)/b}(cosθr+cosθf)·cosθf/sin2(θf+θr)

Wherein, φ=(M/2)+Pcos η

ε＝{G·M(j-z)+μ·W(c-z)+2μ’·P(a-z)}/b

h＝{G·M·y+2μ”·P·d+μ·W·k}/b

Determine described angle θ f (rad) and θ r (rad) so that utilize loading Fr ' that the opposition side inclined-plane of moving body center of gravity side of the bearing of loading Ff (gf) that the inclined-plane of moving body center of gravity side of the bearing in the moving direction downstream that above-mentioned formula calculates bears and moving direction upstream side bears (gf) on the occasion of.

3. image device according to claim 1 is characterized in that,

With the 1st and the 2nd guide rail and described axis of guide configured in parallel, and spline parts and crimping are set on described moving body the pressing component that the 2nd guide rail slides, these spline parts the 1st guide rail at the direction of rotation butt that with the axis of guide is the moving body at center and are slided,

If the quality of moving body is M, acceleration during the acceleration of moving body is G, the loading that acts on the 1st guide rail from the spline parts is W, coefficient of friction between the 1st guide rail and the spline parts is μ, the crimp force that acts on the 2nd guide rail from pressing component is P, and the coefficient of friction between the 2nd guide rail and the pressing component is μ ', and the coefficient between the axis of guide and the bearing is μ "; acting on the angle that the crimp force of the 2nd guide rail and vertical direction form from pressing component is η

In vertical direction, if the distance from the contact position of the axis of guide and bearing to the application point of the locomotivity of moving body is z, be c to the distance of the contact position of the 1st guide rail and spline parts, be j to the distance of the position of centre of gravity of moving body, distance to the contact position of the 2nd guide rail and pressing component is a

In the horizontal direction vertical with the moving direction of moving body, if the distance from the contact position of the axis of guide and bearing to the position of centre of gravity of moving body is y, distance to the contact position of the 1st guide rail and spline parts is d, is k to the distance of the contact position of the 2nd guide rail and pressing component

At the moving direction of moving body, the distance of shaft centers of establishing two bearings is from being b,

Ff’＝{φ+ε+h·tanθr}·cosθr/sin(θf+θr)

-2φ{(μ”·z)/b}(cosθr+cosθf)·cosθr/sin2(θf+θr)

Fr＝{φ-ε+h·tanθr}·cosθr/sin(θf+θr)

+2φ{(μ”·z)/b}(cosθr+cosθf)·cosθf/sin2(θf+θr)

Wherein, φ=(M/2)+Pcos η

ε＝{G·M(j-z)+μ·W(c-z)+2μ’·P(a-z)}/b

h＝{G·M·y+2μ”·P·d+μ·W·k}/b

Determine described angle θ f (rad) and θ r (rad) so that utilize loading Ff ' that the opposition side inclined-plane of moving body center of gravity side of the bearing in the moving direction downstream that above-mentioned formula calculates bears (gf) and the loading Fr (gf) that bears of the opposition side inclined-plane of the moving body center of gravity side of the bearing of moving direction upstream side on the occasion of.

4. image device according to claim 2, it is characterized in that, the maximum of the moment that acts on the described moving body in moving because of external disturbance is made as Mm (gfmm), make loading Ff (gf) that the inclined-plane of moving body center of gravity side of the bearing in described moving direction downstream bears, and the loading Fr ' that bears of the opposition side inclined-plane of the moving body center of gravity side of the bearing of described moving direction upstream side (gf) satisfy following relation:

Ff·cos{π/2-(θf+θr)}·b/2＞Mm

Fr’·cos{π/2-(θf+θr)}·b/2＞Mm。

5. image device according to claim 3, it is characterized in that, the maximum of the moment that acts on the described moving body in moving because of external disturbance is made as Mm (gfmm), make loading Ff ' that the opposition side inclined-plane of moving body center of gravity side of the bearing in described moving direction downstream bears (gf), and the loading Fr (gf) that bears of the inclined-plane of the moving body center of gravity side of the bearing of described moving direction upstream side satisfy following relation:

Ff’·cos{π/2-(θf+θr)}·b/2＞Mm

Fr·cos{π/2-(θf+θr)}·b/2＞Mm。

6. image device according to claim 2, it is characterized in that, make loading Fr ' that the opposition side inclined-plane of moving body center of gravity side of the bearing of loading Ff (gf) that the inclined-plane of moving body center of gravity side of the bearing in described moving direction downstream bears and described moving direction upstream side bears (gf) about equally.

7. image device according to claim 3, it is characterized in that, make loading Ff ' that the opposition side inclined-plane of moving body center of gravity side of the bearing in described moving direction downstream bears (gf) and the loading Fr (gf) that bears of the inclined-plane of the moving body center of gravity side of the bearing of described moving direction upstream side about equally.

8. according to claim 2 or 3 described image devices, it is characterized in that, angle θ f (rad) and θ r (rad) that two inclined-planes determining described bearing form with vertical direction respectively, and make their satisfied abs[Δ (μ W+2 μ ' P+ μ " T)/Δs { 57.3 (θ f+ θ r) } that concerns]≤2.

9. image device according to claim 1 is characterized in that, in the bearing at moving direction two places that are disposed at described moving body, two inclined-planes are different with angle θ f (rad) and θ r (rad) that vertical direction forms respectively.

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